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Novel Tablet Inspections Systems for use in the Continuous Manufacturing of Tablets

Background  Enhancing the flexibility of operations is now a major priority for pharmaceutical manufacturers so they can quickly adapt to change & accommodate a wider range of products (inc. personalized medicines). These market forces drive the requirement for multi-tasking equipment, handling multiple products while reducing change-over times. The demand for modular plant for tablet production is one example of a larger current trend which has been evidenced recently by the announcement from Pfizer of a joint venture with GSK to design the next-generation of portable, continuous, miniature and modular (PCMM) oral solid dose development and manufacturing Units. 

Tablets still represent the majority dosage form (>40%). However, many tablets are difficult to manufacture by the simple, adaptive & flexible process of direct compression due to poor feed stock control (flow&mixing) & poor compaction. These drugs are instead processed by wet granulation, a large-scale, multiple-step batch process (blending, granulation, drying &screening). To take advantage of this business opportunity (i.e. to increase the use of direct compression in the industry) requires process enging solutions, with integrated process analytical technology & feedback/forward control to adapt process to material inputs, coupled to new expertise in materials characterization and end-user validation. DMU’s focus is to develop novel process analytical technologies that can monitor critical parameters and materials attributes that are currently inaccesible by conventional technologies, such as near infrared and Raman spectrroscopy. 
Description This PhD project will research the use of a novel approach to the in-line characterization and quality control of tablets. Our unique approach is based on the speckled image (captured by CCD camera) which is generated through the diffuse reflectance of laser light from the surface and sub-surface micro-structure of a tablet. The technique is known as Intelligent laser speckle classification (ILSC). The experimental work will involve the preparation of powder blends (for direct compression) and granules (produced by wet granulation), followed by the compression of these materials into tablets using a rotary tablet press. By controlling the material variables at a range of scale lengths, from the molecular (e.g. polymeric chain length of binders and disintegrants) through the mesoscale of the grain size of the powders and the size of the granules, to the macroscopic (e.g. density of the tablet), we expect to be able to establish the specific relationships between the microstructure of the tablet and the laser speckle image. Tablet microstructure will be analysed independently by a range of techniques, including SEM, mercury porosimetry and the more novel method based on terahertz imaging (to map the surface density of the tablet). It is expected that the new laser-speckle imaging sensor will be used within a production line to monitor excursions from the control space that might lead to tablet defects, by providing micro-scale information that is currently unachievable with existing technologies. 

For further information contact:

Prof Geoff Smith

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